The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. These advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling-down also requires associated improvements in semiconductor manufacturing and processing equipment.
One process commonly used in semiconductor manufacturing is applying a photoresist layer to the semiconductor device during manufacturing. A photoresist may be positive or negative and is generally known as a light-sensitive material used in photolithography to form a patterned coating on a surface of the semiconductor device. This patterned coating allows processes, such as conventional implantation processes to implant various dopants in the applied patterns onto the semiconductor substrate/wafer. After these implantation processes, the photoresist is generally removed using one or more dry etching (e.g., ashing, plasma etching (O3, CF4), etc.) and/or wet etching (e.g., Caros' clean, H2SO4/H2O2, etc.) processes. It has been observed that conventional implantation processes result in organic photoresist hardening due to a C—C bond formation (e.g., bond energy ˜350 kJ/mol), leaving a carbon crust that cannot dissolve in most solvents and is thus very difficult to remove. Another problem is that the dry etching process generally damages the substrate (e.g., oxide loss), thereby causing the semiconductor device to suffer from reduced electric performance, lower yield productivity, and higher cost of manufacturing. Wet etching alone could prevent the substrate damage, but traditional wet etching methods leave crosslinking carbonized photoresist (PR) crust particles on the substrate. These particles can also negatively influence the electrical performance of the semiconductor device.
Accordingly, what is needed is a method that addresses the above-stated issues.